Spatial light modulators or SLMs are used in various applications, including display systems, optical information processing and data storage, printing, and maskless lithography. One particularly useful type of microelectromechanical systems (MEMS) SLM is a diffractive spatial light modulator (SLM), such as a Grating Light Valve (GLV™) commercially available from Silicon Light Machines, Inc., of Sunnyvale, Calif. GLVs™ are ribbon-type SLM that use electrostatic forces to move actuators or ribbons to produce diffraction between light reflected from adjacent actuators, thereby modulating light incident thereon. The incident light beam can be modulated in intensity, phase, polarization or direction.
Drive circuitry or drivers to generate signals to operate SLMs are made using CMOS or other semiconductor fabrication technologies, which are similar to but distinct from and often incompatible with fabrication technologies used to fabricate the SLM. Thus, SLMs are typically built on a substrate separate from that used to form some or all the associated drivers, and are typically connected to the drivers by wire bonds. In particular, existing SLM drivers generally include a number of external digital-to-analog converters (DACs) to convert digital imaging signals to analog signals used to drive the SLM. Shortcomings of existing SLMs using drivers with external DACs include larger size, due to the need for a separate substrate for the external DACs, the inclusion of additional wire bonding pads on the SLM substrate, lower operating speeds due to delays introduced by the wire bonds in the signal path to the SLM, and higher costs of the external DACs, which must be high speed DACs to offset, at least in part, delays introduced by the wire bonds.
Accordingly, there is a need for a monolithic SLM module including integrated drivers and a manufacturing process combining the SLM and substantially all of its associated drivers, including DACs, into a single integrated circuit (IC) fabricated on single substrate.